DEAINAGE OF WET LANDS OF SOUTHERN LOUISIANA. 63 



and discharged over the levee by means of pumps. These internal vpater 

 courses usually consist of lateral ditches w^hich collect the water from the 

 fields, and reservoir canals which receive the water from the laterals and carry 

 it to the pumping plant. 



Lateral Ditches. 



On the typical wet prairie reclamation district the land is so nearly level 

 that a regular layout of ditches is desirable rather than a location designed 

 with a view to taking advantage of such slight surface slopes as may exist. 

 The ditches should be cut in parallel lines and at such a spacing as will corre- 

 spond to the character of the land. In the newly reclaimed land that has a 

 deep layer of muck, ditches spaced 330 feet apart should give suflScient outlet 

 both for surface and underdrainage, and after some years of cultivation, when 

 the soil has become more impervious, intermediate ditches can be cut, making 

 the spacing 165 feet. This divides the land into 5 and 10 acre tracts when the 

 ditches are constructed in the usual lengths of one-fourth and one-half mile, re- 

 spectively. Ditches with 4-foot tops, IJ-foot bottoms, and depths of 4 feet 

 should give sufficient capacity unless they are too long or become badly choked 

 with weeds and grass. In practice on drainage districts in this section it has 

 been found that in flat land such ditches can be made one-fourth mile long with 

 good results, and they have in a few eases worked fairly well at a length of one- 

 half mile. However, this greater length is not recommended, as the ditch must 

 be maintained in almost perfect condition in order to give satisfactory drainage. 

 Such ditches can be cut by hand labor for about 5 or 7 cents per cubic yard. 



Traction ditchers which will operate on soft prairies have been in use for 

 some time and will compete with hand-labor prices and cut about the same class 

 of ditch ; however, where there is much sunken timber or stumps the work must 

 be done by hand. On the softer prairies these traction ditchers can not be used 

 imtil some months after the tract has been drained and the land has become 

 somewhat solid. Ditches can be cut with a heavy wooden-framed plow, espe- 

 cially built for the purpose, drawn across the strips of land between the reser- 

 voir canals by cables and pulling engines mounted on barges. Ditches can be 

 cut in this manner as soon as the water is off the surface, and thus the bringing 

 of the land under cultivation will be hastened by several months. Field ditches 

 on this class of land require a great deal of attention for the first few years 

 after cutting to keep them serviceable. A soft semifluid mud gradually fills 

 the ditches and water-loving grasses grow very rapidly. Where ditches have 

 been cut with a plow they can readily be cleaned by drawing the plow through 

 them. This method, however, will deposit most of the mud in the reservoir 

 canal and will eventually reduce the area of the latter very materially. 



Practice in this section has shown that to keep such ditches in a serviceable 

 condition the grass and weeds should be cut out of them two or three times a 

 year, and that every two years about 1 cubic foot of material i)er linear foot of 

 ditch must be excavated. The total yearly cost, including interest on first cost, 

 maintenance, and rental of land consumed in ditch, is about 55 cents per 100 

 feet of ditch, or $1.40 per acre for a spacing of 165 feet. In the firmer and more 

 open soils tile might well be used to replace a considerable number of the 

 ditches. The interest on the cost of such tile drains would amount to 30 cents 

 per year for each 100 feet of drain; no maintenance or rental of land consumed 

 should be charged. For a spacing of 165 feet this would make a charge of 80 

 cents per acre per year, or would be an annual saving of 60 cents per acre 

 over open-ditch drainage. The action of eflScient tile drains would also be 

 more uniform. In the case of the ditch, during the time immediately before 



